The relationship between PCSK9 gene I474V polymorphism and ischemic stroke of Uygur and Han ethnic groups in Xinjiang Uygur Autonomous Region

Abstract

Objective To investigate the frequency distribution of proprotein convertase subtilisin/kexin 9 (PCSK9) gene I474V polymorphisms and their relationship with patients with ischemic stroke (IS) of Uygur and Han ethnic groups in Xinjiang Uygur Autonomous Region. Methods The I474V polymorphism was identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in 407 patients with IS（including 219 Hans and 188 Uygurs）and 425 health controls (including 255 Hans and 170 Uygurs), and some specimens were sequenced. Results (1) Between IS group and control group, the genotypes II and IV had no statistically significant differences in the levels of triglycerides (TG), high-density lipoprotein cholesterol (HDL-C); Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) levels had statistically significant differences; LDL-C levels had also statistically significant differences. Between IS and control groups, TC, LDL, HDL-C levels of genotype II showed statistically significant difference. In the IS group, TC, LDL-C levels of IV genotype were significantly higher than the control group, the difference being statistically significant. (2) There was statistically significant difference in the genotype distribution between IS and control groups (9.5%（77/814） vs 4.5%（38/850）, χ2=16.09, P=0.000). And the distribution of allele frequency was statistically different (18.9% （77/407） vs 8.9%（38/425）, χ2=17.38, P=0.000). (3) The differences of I474V loci IV genotype frequency distribution in Xinjiang Uygurs and Hans were statistically significant (27.7%（52/188） vs 11.4%（25/219）, χ2=17.40, P=0.000; 12.9%（22/170） vs 6.3%（16/255）, χ2=5.57，P=0.018); So did the V allele frenquency distribution (13.8%（52/376） vs 5.7%（25/438）, χ2=15.58，P=0.000; 6.5%（22/340） vs 3.1%（16/510）, χ2=10.44, P=0.001). (4) There was statistically significant difference in the genotype distribution and allele frenquency distribution between IS group and control group in the Xinjiang Uygurs (27.7%（52/188） vs 12.9%（22/170）, χ2=11.79, P=0.001; 13.8%（52/376) vs 6.5%（22/340）, χ2=10.44，P=0.001）; But there was no statistically significant difference in the Hans. Conclusions II and IV genotypes are dominant in the I474V polymorphism loci of PCSK9 gene. The genotype of PCSK9 gene I474V polymorphism is correlated with increasing serum levels of TC and LDL-C. I474V polymorphism is associated with cerebral IS course in Xinjiang region. There is statistically significant difference in the genotype I474V distribution between Uygur and Han groups. I474V polymorphism has a relationship with the occurrence of IS in Xinjiang Uygurs. IV may be a susceptible genotype and V may be a genetic susceptible allele of the Xinjiang Uygurs. Key words: Brain ischemia; Stroke; Serine endopeptidases; Proprotein convertases; Polymorphism, genetic; Uygur nationality; Han nationality